<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <script>
    let arr=[1,23,4,5,567,8,3,2,645,2];
    // => 相当于写了一个 function
    let arr2=arr.map(item=>item > 10);

    alert(arr2);
    </script>
  </head>
  <body>

  </body>
</html>
